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|  MIL-P-48450A(MU)
the respective module specification post-vibration requirements and tests,
the head, body and elbow assemblies shall be examined and tested in accord-
ance with 4.6.3.8 to determine conformance to cleanliness as specified in 3.5.
4.6.3.8 Cleanliness.- Each separate assembly (see 4.6.4) shall be sub-
jected to the tests in 4.6.3.8.1, 4.6.3.8.2 and 4.6.3.8.3 respectively, to
determine compliance with 3.5.
4.6.3.8.1 Body assembly (daylight).- The optical surfaces of the
body assembly shall be visually examined with the unaided eye. While
viewing through each end of the module, inspection for defects shall be
made by the technique of shadowing. While viewing through the eyepiece,
inspection for dirt shall be made by viewing a uniformly illuminated
field having a brightness of approximately 300 apparent foot candles.
The body assembly (daylight) shall conform to the requirements of 3.5a and
3.5b(l).
4.6.3.8.2 Elbow assembly (passive).- The image intensifier tube
shall be de-energized for this portion of the test. With a light source
held close. to the objective window and the eyelens, view the glass com-
ponents of the elbow assembly to determine compliance with the cleanli-
ness requirements of 3.5a. Upon successful completion of this portion of
the test, energize the image intensifier tube from a power source capable
of supplying and maintaining 24 volts DC. The image tube shall be per-
mitted a stabilization period of 15 seconds prior to performing the
cleanliness test. Subsequent to the tube stabilization period, obtain
best focus of the phosphor grain on the screen of the image tube by adjust-
ment of the eyepiece diopter ring. The screen surface of the image tube
shall then be visually inspected for cleanliness in accordance with 3.5b
(2) and shall conform to the requirements specified therein. "Cold" and
"Hot" spots on the screen surface of the image tube shall not be considered
dirt.
4.6.3.8.3 Head assembly.- The optical surfaces of the head assembly
shall be inspected for cleanliness with the unaided eye. While viewing
through each end of the module, inspection for defects shall be made by
the technique of shadowing. While viewing through the exit window, in-
spection for dirt shall be made by viewing the illuminated field speci-
fied in 4.6.3.8.l. The head assembly shall conform to the requirements
of 3.5a and 3.5b(3).
4.6.4 Performance.- To determine compliance with 3.6, the following
tests shall be performed with the complete periscope positioned on the
special test equipment specified in 4.5.2.3.1. A target projector
collimator having a clear aperture of at least 2.0 inches and containing an
appropriate calibrated horizontal and vertical reticle crossline target
test pattern shall be utilized with the specialized test equipment
specified herein. The vertical reticle target line shall be aligned
plumb when in the test position on a qualified level surface and the
target projector collimator shall be adjusted for infinity. The target
projector collimator shall be positioned at the rear of the daylight
body of the periscope so that its optical axis is in alignment with
the line of sight (geometric center) of Lens 8289292. The optical
axis of the target projector collimator shall be aligned parallel
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